1. Field of the Invention
The present invention relates generally to ductwork and more particularly to a damper clip extension for extending a damper assembly control shaft.
2. Description of Prior Art
Ductwork in buildings is usually provided with damper assemblies for manually controlling air flow through the ductwork. In many cases the damper is connected to a control shaft that extends through the duct work to a handle. The handle can be turned to rotate the damper to block the flow of air through the duct. The control shaft extends from the duct a very short distance. In many cases the duct can be wrapped with materials such as insulation. This blocks the access to the handle or makes it difficult to turn the handle. The solution to this problem has been to provide damper clip extensions connected by one end to the control shaft, and by the other end to a handle. The problem with the prior art extensions are that these extensions have been difficult or impossible to manufacture and expensive to machine.
For example, U.S. Pat. No. 4,646,715 discloses a damper clip extension having a control shaft with a threaded end having a first transverse configuration of two oppositely facing arcuate sides merging with two oppositely facing flat sides. An extension is provided that includes a closed end and an open end, wherein the open end includes a bore for receiving the threaded end of the control shaft. The open end further includes two open sides, so that the control shaft is exposed once received by the open end of the extension. The closed end of the extension has a similar transverse configuration as the control shaft threaded end. The problem with this design is that the threads in the open end of the extension are difficult and impractical to machine. This results in a device that cannot be made, or cannot be made at a practical price.
Additionally, there is no means provided for preventing the extension from becoming loosened from the control shaft over an extended time period.